Classification
541 - Physical chemistry
936
620 - Engineering & allied operations
177
530 - Physics
144
546 - Inorganic chemistry
71
547 - Organic chemistry
71
543 - Analytical chemistry
66
539 - Modern physics
63
572 - Biochemistry
63
621 - Applied physics
58
660 - Chemical engineering
56
536 - Heat
30
571 - Physiology & related subjects
26
363 - Other social problems & services
22
548 - Crystallography
21
551 - Geology, hydrology & meteorology
18
333 - Economics of land & energy
17
549 - Mineralogy
17
531 - Classical mechanics; solid mechanics
14
615 - Pharmacology & therapeutics
12
616 - Diseases
12
577 - Ecology
11
537 - Electricity & electronics
8
540 - Chemistry & allied sciences
7
670 - Manufacturing
7
500 - Natural sciences & mathematics
6
520 - Astronomy & allied sciences
6
534 - Sound & related vibrations
6
641 - Food & drink
6
664 - Food technology
6
538 - Magnetism
5
610 - Medicine & health
5
613 - Personal health & safety
5
628 - Sanitary & municipal engineering
5
580 - Plants (Botany)
4
519 - Probabilities & applied mathematics
3
542 - Techniques, equipment & materials
3
630 - Agriculture & related technologies
3
631 - Techniques, equipment & materials
3
003 - Systems
2
501 - Philosophy & theory
2
515 - Analysis
2
624 - Civil engineering
2
629 - Other branches of engineering
2
005 - Computer programming, programs & data
1
006 - Special computer methods
1
330 - Economics
1
523 - Specific celestial bodies & phenomena
1
532 - Fluid mechanics; liquid mechanics
1
533 - Gas mechanics
1
576 - Genetics & evolution
1
more ...